Abstract:

The interest towards dynamic simulation in process industry is increasing all the time. The huge development in computing power has made it possible to run larger and more accurate dynamic models in real time. In this thesis a dynamic simulation model of rotary lime kiln was developed. Lime kilns are used in chemical recovery processes of a pulp mills to convert the calcium carbonate formed in causticizing into lime, which can be then reused for causticizing. Because of the many different phenomena inside the kiln, it is very challenging to build a fast and an accurate enough model. The most important chemical and physical phenomena are modeled in this project. These are water evaporation, calcining reaction, solid movement, gas flow, heat transfer inside the kiln, heat transfer through the wall and mass transfer between solid and gas phase. In spite of these different phenomena simulation speed faster than real time was achieved. The purpose of this project was to develop a general model for the lime kiln which can then be specified to some particular kiln.